Perplexed by the appearance of mysterious white sediment inside vials of vaccine produced by an Indian subsidiary of Sanofi-Aventis, the World Health Organization has suspended the purchase and distribution of its Shan5 jab. According to Sanofi, the move comes as a "precautionary measure pending outcome of an investigation of vaccine quality."

A spokesperson for the WHO insists that there have been no safety problems yet discovered with the vaccine, a shot that provides protection against diphtheria, pertussis, tetanus, Haemophilus influenza B, and hepatitis B. However, even after vigorous shaking, the sediment was hard to disperse. And that, she adds, is a rare problem.

India's Shantha Biotechnics landed a contract valued at $340 million last fall to supply the vaccine to the WHO through 2012--just months after Sanofi bought it.

- here's the Wall Street Journal report

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